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Earth’s Magnetic Field
The Earth has a magnetic field as does the Sun and all the planets in the Solar System.
Magnetic fields are generated by the acceleration of charged particles such as electrons.
Charged particles within the Earth are believed to be set in motion by the rotation of the
Earth. The magnetic field is represented by imaginary lines from the north magnetic pole to the south magnetic pole. These lines align with compass direction.
The region around the earth in which the magnetic field is significant is called the magnetosphere. As shown below, two donut shaped regions containing magnetically trapped energized particles are the Van Allen Belts (named after an American physicist that detected them).
The energized particles originate in solar activity, solar wind, flares, and CMEs. The shape of the magnetosphere is influenced by the solar wind. The solar wind compresses and deforms the magnetosphere on the dayside and expands it on the night side. This is called a bow shock. A bow shock is analogous to a ship moving through the ocean pushing the water ahead of it creating an area of higher pressure and creating a drag at the rear of the ship.

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Effects of Solar Activity on the Earth
Ionosphere
The ionosphere is a layer within the upper atmosphere (thermosphere) of the Earth which is made up of charged ions. Although there is intense solar radiation above the ionosphere, the density (few atoms) is so low that ionization is minimal. At the ionosphere, the density of the atmosphere increases and ionization occurs. The ionosphere ends when the density of the gases is such that recombination—ions combining to form stable compounds—occurs. Solar events can change the heights of the different ionized layers and disrupt communications systems.
Auroras
Perhaps the most well known effect of energized particles from the Sun is the occurrence of spectacular light shows in the upper atmosphere called auroras. Where the magnetic field lines intersect the atmosphere, the charged particles collide with atmosphere molecules. Auroras in the northern hemisphere are called aurora borealis (Northern
Lights) and in the southern hemisphere aurora austrialis (Southern Lights). The beautiful auroras are usually red (from nitrogen) or green (from oxygen), but can be many shades in between.
Satellite, Communications, and Power Disturbances
With the ever-increasing use of satellites in the modern world, the existence of solar disturbances must be continually monitored. There are approximately 600 operational military, commercial, and civilian satellites currently orbiting the earth within the magnetosphere. When solar events disturb and compress the magnetosphere, it can and has caused satellite failures and disruptions.

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Excess charged particles can also cause power surges in ground transmission lines that can result in power outages. In 1989, geomagnetically induced currents caused a power grid in Quebec to fail and resulted in a 9-hour power outage.
For more information…
1. http://solar-center.stanford.edu/magnetism/magneticfields.html
This site gives good background information on magnetic fields and magnetic forces.
2. http://image.gsfc.nasa.gov/poetry/NASADocs/magbook2002.pdf
Exploring the Earth’s magnetic field is a satellite guide to the magnetosphere that
also has a serious of lab activities dealing with Earth’s magnetism, auroras, magnetic
storms, and space weather.
3. http://image.gsfc.nasa.gov/poetry/storm/storms.html
This is an extremely useful site that details the effects of solar storms on the Earth and
and humans.
4. http://www.windows.ucar.edu/spaceweather/basic_facts.html
This site is titled “Basic Facts about Space Weather” and has real time data which
includes daily aurora information.
5. http://www.windows.ucar.edu/
This entire site offers information, activities, and even games dealing with space and
space weather.